nhờ đó truy vấn này có thể giúp:
SELECT min(c1)
from (
select expression1 as c1
union all
select expression2 as c1
union all
select expression3 as c1
)
nhờ đó truy vấn này có thể giúp:
SELECT min(c1)
from (
select expression1 as c1
union all
select expression2 as c1
union all
select expression3 as c1
)